Discussion
Future studies will have to address the diagnostic and prognostic value of MLC1-specific antibodies in neuroinflammatory disorders such as MS and characterize the functional role of MLC1 expression in neurons and astrocytes.
Methods
We combined polyclonal B-cell stimulation of peripheral blood mononuclear cells with a human proteome-wide protein microarray to identify target antigens of MS by comparing samples from 20 patients with MS with 9 age-matched and sex-matched healthy controls.
Results
Our results corroborate the existing concept of a highly diverse autoimmune response in MS. Yet, a significantly elevated antibody response against the membrane protein modulator of VRAC current 1 (MLC1) was noted in B-cell culture supernatants and serum samples of patients with MS. Furthermore, significantly elevated titers to MLC1 were observed in the CSF of patients with neuroinflammatory diseases other than MS. Neurons and astrocytes were identified as the main cell types expressing MLC1 in the brain of a patient with MS. Injection of anti-MLC1 antibodies into mice with EAE led to strong in vivo binding to cerebral cortical neurons and to the death of 4 of the 7 injected mice.